The surface diffusion of Al adatoms during metal-organic vapour phase epitaxy of

AlN was investigated, using sapphire substrates with different mis-orientations. It

was found that the diffusion length during modified migration-enhanced epitaxy

(MEE) was about 40nm and comparable to that of conventional MEE under the

current growth conditions. The enhancement of the diffusion length by alternating

supply of source precursors was also demonstrated. The screw dislocation density

in the modified-MEE-grown AlN was extracted to be as low as 2.2 x 106/cm2 from

X-ray diffraction, while the chemical etching by KOH solution revealed an etch pit

density of 1.0 x 106/cm2, both of which indicated its superior structural properties.

The chemical etching also evidenced that the grown AlN has Al polarity.

Surface Diffusion During Metalorganic Vapor Phase Epitaxy of AlN. R.G.Banal,

M.Funato, Y.Kawakami: Physica Status Solidi C, 2009, 6[2], 599-602